Various memory cards having different specifications are commercially available. Memory cards can be classified as large memory cards and small memory cards based on size. Large memory cards comprise MMC (MultiMediaCard), CF (CompactFlash™ Card), SD (Secure Digital), SM (Smart Media), and MS (Memory Stick) available from SONY Corporation. MMCs, CFs, and SDs not only have large market shares but also are widely used as main memory cards in DSCs (Digital Still Cameras), MP3 players, and other multimedia devices. Also, the specifications of SD and MMC are complied with the miniaturization of Smart Phone. Thus, SD and MMC are taken as standard storage devices by major mobile phone manufacturers such as Samsung Electronics, Nokia, and Motorola. Regarding small memory cards, they comprise miniSD, microSD (T-Flash), RSMMC, MMC micro, MS Duo, and Memory Stick Micro (M2). Small memory cards are advantageous for being compact, lightweight, energy saving, durable, and rewritable. Thus, small memory cards are widely mounted in various portable electronic products including PDA (Personal Digital Assistant), DSC, Digital Music player, and Smart Phone. Further, small memory cards have certain advantages and relatively large market shares because they concentrate on markets different from that of large memory cards.
A variety of card readers for reading data from memory cards are commercially available. A conventional card reader is shown in FIG. 1 and comprises a circuit board 10, a housing 20, a USB (Universal Serial Bus) connector 16, and a port 12. The circuit board 10 is mounted in the housing 20. The housing 20 comprises a front opening 23 aligned with the mouth of the port 12. A memory card 30 is adapted to insert in the port 12 through the opening 23. The housing 20 further comprises a rear opening 24. The USB connector 16 is projected from the rear opening 24 to expose from the housing 20. The USB connector 16 is adapted to insert into a USB port of a notebook computer (not shown). An inner end of the USB connector 16 is fixedly formed with the circuit board 10 and is electrically connected thereto. An outer end of the USB connector 16 is extended out of the circuit board 10. The port 12 is fixedly formed above the circuit board 10 and is disposed opposite the USB connector 16. The port 12 comprises a seat 13, an insertion slot 14 in the seat 13, and a plurality of metal contacts 15 electrically connected to the seat 13 which is electrically connected to the circuit board 10 again. As such, in response to inserting the memory card 30 in the insertion slot 14, a plurality of conductive terminals (not shown) of the memory card 30 are in contact with the contacts 15. Next, insert the USB connector 16 into a notebook computer (not shown). A CPU (central processing unit) of the notebook computer is adapted to read data from the memory card 30 or write data thereinto via the connected USB connector 16, the circuit board 10, and the contacts 15. Moreover, referring to FIG. 1 again, at least one LED (light emitting diode) 17 is mounted on the circuit board 10. The LED 17 is adapted to emit light for indicating an operating state of the card reader in response to inserting the memory card 30 in the insertion slot 14 and inserting the USB connector 16 into the notebook computer.
As stated above, memory cards having different specifications are adapted to operate in conjunction with various electronic products. Thus, card readers having different specifications are available on the market for meeting different needs of vast users. For example, a user has a number of different electronic products (e.g., DSC, PDA, Smart Phone, etc.) each having a unique insertion slot for receiving an inserted memory card having different specifications in order to read data from the memory card (e.g., SD, Memory Stick, microSD (T-Flash), etc.). However, the user is not able to either operate an electronic product to read data from a memory card having different specifications inserted into the insertion slot of the electronic product or operate a notebook computer to read data from a memory card having different specifications inserted into the USB connector of the notebook computer. Thus, with respect to each electronic product a user has to buy a number of suitable adapters or card readers having different specifications in cooperation therewith in order to read data from a memory card having different specifications inserted into the insertion slot. Inevitably, users have to spend more money on buying these devices (i.e., bear a great financial burden upon users) and it is very inconvenient in use. A card reader capable of reading one of a variety of memory cards is also commercially available recently. The card reader has a plurality of insertion slots having different specifications for reading data from many memory cards having different specifications. However, this type of card reader is expensive, bulky, and not easy to carry. It is thus a waste for a user to buy such unpractical card reader since the user may never have a chance to use certain or even many insertion slots of the card reader to read data from inserted memory cards.
In view of above, it is thus desirable among card reader manufacturers to provide a card reader such that a user may operate a notebook computer to read data from a memory card having certain specifications via a USB connector of the notebook computer or write data into the memory card, and the user may also take the card reader as an adapter for the memory card and insert same into an insertion slot complied with the specifications of a different memory card of another electronic product in order to read data from the memory card or write data thereinto via another electronic product. By configuring as above, a number of advantages are obtained when a user only has to carry a memory card shaped card reader. The advantages include obtaining features of both card reader and adapter, carrying an adapter and a card reader at the same time being not necessary, and saving money.